Lost about 2# boost after intake leak repair

[Kiwi_Camaro_2010]

At the back is the only normal spot I know of for IAT sensor plus MAP sensor for a Whipple. Wiring for IAT normally runs on driver side of whipple while wiring for MAP is on passenger side. Think if it wasn't plugged in you would get a code flash up.

[mercedestech]

The older whipples didnt have the iat in the rear, they used the maf's iat. Whipple sells a kit to retrofit the older kits. How do your fuel trims look? See if the pcm is adding fuel to compensate for an intake leak....it is really easy to roll one of the orings over on the intake. Also make sure that belt isn't slipping.

[Inferno LSX]

I went through 2 different bypass valves and 2 supercharges before I got one that had a non sticking bypass valve. I even took a day off of work and drove up to Fresno to Whipple. Very nice people and Art Whipple is a very nice guy. What size pulley are you running? I made about 10PSI on the 3.875 pulley. I've since installed Water/Meth and TPiS 102mm TB and now make 12.5 PSI on the same pulley. Your bypass might not be 100% closed under boost bleeding off 1PSI. Good luck hope you get is figured out.

[2SSCAMARO]

Originally Posted by SSlim

The coolant is topped off and looks good.

I am wondering if the gauge is off (adm boost and AF) or a line/fitting to the gauge is leaking. The car pulls hard I am just not seeing the same reading on the gauge as before. I suppose I could take it back to the dyno and see if we still are making the same power. He'll if I am getting over 600 with 10lbs of boost I am good with that.

Originally Posted by SSlim

New question... From the install manual page 50 there should be an air intake sensor on the back of the intake. I think that maybe unplugged or blocked off. Why would someone do that? Can you be pulling intake temp from someplace else?

Do a log of the IAT and boost through the OBD port with a logger.

[SSlim]

New belt is coming since the other was a little chewed up from sliping.

What would the fuel trims do that would indicate a leak? I was watching them on the log last night but have no idea what I am looking for.

The logger is getting IAT reading. So either that sensor is there and I can not feel it or they are using the MAF or something for temp.

I have 3.75 pulley.

What would boost look like on the logger? I think I might try another gauge just to be sure the reading is right. It pulls like a rapped ape, but don't know that I would be able to tell the difference with a 1# boost loss.

[2SSCAMARO]

Originally Posted by SSlim

New belt is coming since the other was a little chewed up from sliping.

What would the fuel trims do that would indicate a leak? I was watching them on the log last night but have no idea what I am looking for.

The logger is getting IAT reading. So either that sensor is there and I can not feel it or they are using the MAF or something for temp.

I have 3.75 pulley.

What would boost look like on the logger? I think I might try another gauge just to be sure the reading is right. It pulls like a rapped ape, but don't know that I would be able to tell the difference with a 1# boost loss.

Fuel trims vary day to day based on temp, humidity, DA, RPMS, etc. If you had done numerous logs at a steady RPM on a flat stretch of road at roughly the same AAT on a fully warmed up engine and knew what your average fuel trims were and now found them to be consistanty shifted more positive, it would be an indication of a vacuum leak introducing unmetered air that would cause the LTFT's to be leaner than before.

The boost would be shown on the log as MAP and could be shown in MB's or PSI depending on what logging device is used. Log the MAP, IAT, and any other PID you want, then post up the log.

[mercedestech]

Originally Posted by 2SSCAMARO

Fuel trims vary day to day based on temp, humidity, DA, RPMS, etc. If you had done numerous logs at a steady RPM on a flat stretch of road at roughly the same AAT on a fully warmed up engine and knew what your average fuel trims were and now found them to be consistanty shifted more positive, it would be an indication of a vacuum leak introducing unmetered air that would cause the LTFT's to be leaner than before.

The boost would be shown on the log as MAP and could be shown in MB's or PSI depending on what logging device is used. Log the MAP, IAT, and any other PID you want, then post up the log.

ALthough this is true, fuel trims on a normally functioning engine will be close to the middle of the range. If the pcm is adding fuel to the point of being close to the high limit, there is a problem. A leak from the intake seals will show a very high stft, and eventually ltft before it actually flags a fault and turns the check engine light on. This is all I was getting at.

Boost is fixed based on the pulley given the same iat etc.. If he is seing 1.5 lbs less after the repair, something is wrong as long as the driving conditions temps etc are similar. Either the blower is not capeable of mechanically producing boost due to belt slippage, or there is a leak. The main point being the whipple and/or pcm does not control boost based on any of the sensors inputs. It can drastically alter power output based on timing, fuel injector pulse width etc, but the boost value is a measurement of a mechanical event. The only exception would be if the pcm is closing the throttle limiting air flow into the supercharger. Given all things equal, iat temp, mechanical condition of the supercharger and engine, it should make the same boost post repair as it did before.

[2SSCAMARO]

Originally Posted by SSlim

New belt is coming since the other was a little chewed up from sliping.

What would the fuel trims do that would indicate a leak? I was watching them on the log last night but have no idea what I am looking for.

The logger is getting IAT reading. So either that sensor is there and I can not feel it or they are using the MAF or something for temp.

I have 3.75 pulley.

What would boost look like on the logger? I think I might try another gauge just to be sure the reading is right. It pulls like a rapped ape, but don't know that I would be able to tell the difference with a 1# boost loss.

Originally Posted by 2SSCAMARO

Fuel trims vary day to day based on temp, humidity, DA, RPMS, etc. If you had done numerous logs at a steady RPM on a flat stretch of road at roughly the same AAT on a fully warmed up engine and knew what your average fuel trims were and now found them to be consistanty shifted more positive, it would be an indication of a vacuum leak introducing unmetered air that would cause the LTFT's to be leaner than before.

The boost would be shown on the log as MAP and could be shown in MB's or PSI depending on what logging device is used. Log the MAP, IAT, and any other PID you want, then post up the log.

Originally Posted by mercedestech

ALthough this is true, fuel trims on a normally functioning engine will be close to the middle of the range. If the pcm is adding fuel to the point of being close to the high limit, there is a problem. A leak from the intake seals will show a very high stft, and eventually ltft before it actually flags a fault and turns the check engine light on. This is all I was getting at.

Boost is fixed based on the pulley given the same iat etc.. If he is seing 1.5 lbs less after the repair, something is wrong as long as the driving conditions temps etc are similar. Either the blower is not capeable of mechanically producing boost due to belt slippage, or there is a leak. The main point being the whipple and/or pcm does not control boost based on any of the sensors inputs. It can drastically alter power output based on timing, fuel injector pulse width etc, but the boost value is a measurement of a mechanical event. The only exception would be if the pcm is closing the throttle limiting air flow into the supercharger. Given all things equal, iat temp, mechanical condition of the supercharger and engine, it should make the same boost post repair as it did before.

SSlim asked two questions. I merely tried to answer his questions. Do you feel my response to his questions is incorrect? It appears he does not currently know for sure that his WOT boost is in fact not what it was before the repair because he has not logged the boost to see if it is the same reading he is seeing on the gage.